Background

Melatonin is a hormone produced in the brain by the pineal gland from the amino acid tryptophan. The production and release of melatonin are stimulated by darkness and decreased by light, suggesting that melatonin is involved in circadian rhythm (the internal body clock) and regulation of diverse body functions. Levels of melatonin in the blood are highest prior to bedtime.

The most common use of melatonin is to aid in sleep. The strongest evidence supporting the use of melatonin is for delayed sleep phase syndrome, insomnia in children and the elderly, jet lag, and sleep problems in people with behavioral, developmental, or mental disorders. The weakest evidence in support of melatonin is for work shift sleep disorder. Good evidence in support of melatonin for other uses is lacking.

New drugs that block the effects of melatonin are being developed. These include BMS-214778 and luzindole, and they may have uses in various disorders.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (over 18 years old)

The time of day that melatonin is taken is important. Melatonin impacts circadian rhythms (the internal body clock) differently depending on whether it is taken in the morning, afternoon, or early evening.

For age-related macular degeneration (vision loss with age), three milligrams of melatonin have been taken by mouth nightly at bedtime for six months.

To improve body temperature regulation in the elderly, 1.5 milligrams of melatonin has been taken by mouth nightly for two weeks.

For Alzheimer's disease or cognitive decline, melatonin has been taken by mouth in doses of 1-10 milligrams daily for 10 days up to 35 months.

For inflammation, melatonin has been taken by mouth in doses of 10 milligrams nightly for six months or five milligrams the night before and one hour before surgery.

For asthma, three milligrams of melatonin has been taken by mouth for four weeks.

For withdrawal from benzodiazepines (antianxiety agents), doses of 1-5 milligrams have been taken by mouth daily for from several weeks up to one year.

For cancer, melatonin has been taken by mouth in doses of 1-40 milligrams daily, with 20 milligrams being most common, for several weeks to months. Melatonin has been applied to the skin.

For chronic fatigue syndrome, five milligrams of melatonin has been taken by mouth five hours before bed for three months.

For COPD (chronic lung disorder causing breathing difficulty), three milligrams of melatonin has been taken by mouth nightly two hours before bed for three months.

For circadian rhythm sleep disorders in people with and without vision problems, melatonin has been taken by mouth as a single dose of 0.5-5 milligrams before bed or as a daily dose for 1-3 months.

For delayed sleep phase syndrome, melatonin has been taken by mouth in doses of 0.3-6 milligrams, with five milligrams being most common, daily before sleeping for two weeks to three months.

For delirium, 0.5 milligrams of melatonin has been taken by mouth nightly for up to 14 days.

For depression, six milligrams of slow-release melatonin has been taken by mouth at bedtime for four weeks.

For exercise performance, 5-6 milligrams of melatonin has been taken by mouth one hour before exercise or before bedtime.

For fertility, three milligrams of melatonin has been taken by mouth nightly from the third to fifth day of the menstrual cycle until hormone injection (human chorionic gonadotropin, HCG), or on the day of hormone injection.

For fibromyalgia, 3-5 milligrams of melatonin has been taken by mouth nightly for four weeks to 60 days.

For stomach and intestine disorders, 3-10 milligrams of melatonin has been taken by mouth nightly for 2-12 weeks.

For headache, 2-10 milligrams of melatonin has been taken by mouth nightly for 14 days to eight weeks.

For liver inflammation, five milligrams of melatonin has been taken by mouth twice daily for 12 weeks.

For high blood pressure, melatonin has been taken by mouth in doses of 1-5 milligrams either as a single dose during the day or before bedtime, or daily for 1-3 months.

For high cholesterol, five milligrams of melatonin has been taken by mouth daily for two months.

For insomnia in the elderly, melatonin has been taken by mouth in doses of 0.1-5 milligrams at or two hours before bedtime for up to several months, in the form of melatonin-rich night milk or slow-release Circadin®. A dose of 0.5 milligrams has been placed in the cheek for four nights.

For jet lag, 0.1-8 milligrams of melatonin has been taken by mouth on the day of travel (close to target bedtime at destination), then daily for several days, in the form of standard or slow-release melatonin (Circadin®).

For memory, three milligrams of melatonin has been taken by mouth before testing.

For menopause, three milligrams of melatonin has been taken by mouth nightly at bedtime for 3-6 months.

For Parkinson's disease, doses of 3-50 milligrams have been taken by mouth nightly before bed for 2-10 weeks. (High doses of 3-6.6 grams of melatonin have also been taken by mouth daily; however, these doses were used in an older 1972 study and are no longer in use.)

For periodic limb movement disorder, three milligrams of melatonin has been taken by mouth nightly for six weeks.

For REM sleep behavior disorder, 3-12 milligrams of melatonin has been taken by mouth daily for four weeks.

For restless leg syndrome, a single dose of three milligrams of melatonin has been taken by mouth.

For sarcoidosis (chronic widespread inflammation), 20 milligrams of melatonin has been taken by mouth daily for one year, then decreased to 10 milligrams for a second year.

For muscle movement problems in people with schizophrenia, 2-10 milligrams of melatonin has been taken by mouth daily.

For seasonal affective disorder (SAD), two milligrams of sustained-release melatonin has been taken by mouth 1-2 hours nightly for three weeks. A dose of 0.5 milligrams of melatonin has been taken under the tongue for six days.

For seizure disorders, doses of melatonin taken by mouth were 3-10 milligrams daily for 2-4 weeks to three months.

For sleep (general), doses of melatonin taken by mouth were 0.3-10 milligrams.

For sleep disorders in people with behavioral, developmental, or mental disorders, 0.1-10 milligrams of melatonin has been taken by mouth daily for up to one year.

For sleep disturbance in Alzheimer's disease, 1.5-10 milligrams of melatonin has been taken by mouth nightly for 10 days to 35 months, together with light exposure or in the form of capsules.

For sleep disturbance in those with asthma, three milligrams of melatonin has been taken by mouth for four weeks.

For sleep disturbance in those with autism, 0.75-10 milligrams of melatonin has been taken nightly before bedtime for two weeks to six months.

For sleep disturbance in those with COPD, three milligrams of melatonin has been taken by mouth nightly.

For sleep disturbance in those with cystic fibrosis, three milligrams of melatonin has been taken by mouth nightly at bedtime for 21 days.

For sleep disturbance in those with depression, 0.5-10 milligrams of melatonin has been taken by mouth for 3-4 weeks, in addition to regular therapy.

For sleep disturbance in healthy people, 0.1-80 milligrams of melatonin has been taken by mouth, generally nightly before bed for one or several days up to 26 weeks. A dose of 50 milligrams has been injected into the vein.

For sleep disturbance in people undergoing hemodialysis, three milligrams of melatonin has been taken by mouth for six weeks.

For sleep disturbance in hospitalized and medically ill people, 3-5.4 milligrams of melatonin has been taken by mouth nightly.

For sleep disturbance in people with a learning disability, 0.5-9 milligrams of melatonin has been taken by mouth for 32-73 days.

For sleep disturbance in those with Parkinson's disease, 3-50 milligrams of melatonin has been taken by mouth at bedtime for 2-4 weeks.

For sleep disturbance after surgery, five milligrams of melatonin has been taken by mouth for three nights.

For sleep disturbance in people with mental disorders, 2-12 milligrams of melatonin has been taken by mouth daily before resting for up to 12 weeks

For sleep disturbance in people with traumatic brain injury, five milligrams of melatonin has been taken by mouth for one month.

For sleep disturbance in people with tuberous sclerosis complex (a genetic disorder causing tumors to grow in brain and other organs), five milligrams of melatonin has been taken 20 minutes before bed for two weeks.

For smoking, 0.3 milligrams of melatonin has been taken by mouth 3.5 hours after nicotine withdrawal.

For surgery, 3-15 milligrams of melatonin has been taken by mouth or placed under the tongue, and 0.05-0.2 milligrams per kilogram has been placed under the tongue, either alone or with other sedatives, typically 90 minutes before surgery or the night before and 90 minutes before surgery. For anxiety or sedation before surgery, 3-10 milligrams and/or 0.05-0.5 milligrams per kilogram of melatonin have been injected into the vein, either alone or with other sedatives before surgery.

For tardive dyskinesia (uncontrolled, repetitive movements), 2-20 milligrams of melatonin has been taken by mouth for 4-12 weeks.

For low platelets, 20 milligrams of melatonin has been taken by mouth nightly for two months.

For ringing in the ears, three milligrams of melatonin has been taken by mouth daily for up to 80 days.

For ulcers, five milligrams of melatonin has been taken by mouth twice daily for 21 days together with other medications.

For nighttime urination, two milligrams of melatonin has been taken by mouth daily for four weeks.

For work shift sleep disorder, 1.8-10 milligrams of melatonin has been taken by mouth up to three times daily for up to six days before daytime sleep after a night shift.

For skin sun damage, melatonin has been applied to the skin in the form of a gel (20-100 milligrams of melatonin in 70% ethanol, in concentrations of 0.05-0.5% in 0.12 milliliters of gel); 0.6 milligrams per meter squared from 15 minutes before to 240 minutes after sun exposure, alone or with vitamins C and E; five percent melatonin in ethanol, propylene glycol, and water; and 5.85 microliters of solutions containing 1.2-5% melatonin, alone or with vitamins C and E.

Children (under 18 years old)

There is limited research on melatonin supplements in children, and their safety is not established. Melatonin may increase seizure risk in children; caution is advised, and use of melatonin should be discussed with a healthcare provider.

For inflammation or respiratory distress syndrome in newborns, 10 doses of melatonin (10 milligrams per kilogram) have been given, with two hours in between the first four doses, four hours in between the fifth and sixth doses, eight hours in between the seventh and eighth doses, and 12 hours in between the ninth and 10th doses.

For circadian rhythm sleep disorders in children with and without vision problems, 3-12 milligrams of melatonin has been taken by mouth daily for eight weeks.

For delayed sleep phase syndrome, 3-6 milligrams of melatonin has been taken by mouth daily for 10-28 days.

For insomnia, 1-5 milligrams of melatonin have been taken by mouth once nightly for up to two months. Doses of 0.05-0.15 milligrams per kilogram of melatonin have been taken by mouth nightly for one week.

For Rett's syndrome, 2.5-7.5 milligrams has been taken by mouth once daily at bedtime for up to two years.

For sedation, 3-6 milligrams of melatonin has been taken by mouth 10 minutes before standard sedation.

For seizure disorder, 1.5-10 milligrams of melatonin has been taken by mouth daily for two weeks to three months.

For sepsis (severe response to infection), two 10-milligram doses, separated by one hour, have been taken by mouth 12 hours after diagnosis.

For sleep disorders in children with behavioral, developmental, or mental disorders, 0.1-10 milligrams has been taken by mouth daily for one week to 72 months.

For sleep disturbance, 2-10 milligrams of melatonin has been taken by mouth nightly before bedtime for four weeks to three months.

For surgery, 0.1-0.5 milligrams per kilogram of melatonin has been taken by mouth in 1-3 doses before surgery, with standard painkillers or anesthesia.

For nighttime urination, five milligrams of melatonin has been taken by mouth nightly for three months.

For pain, a single dose of 10 milligrams per kilogram of melatonin has been injected into the vein.

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Delayed sleep phase syndrome (DSPS)

Delayed sleep phase syndrome is a condition that results in delayed sleep onset despite normal sleep patterns and duration. Studies report that melatonin may help improve the amount of time it takes to fall asleep. More research is needed before further conclusions can be made.

B

Insomnia (children)

According to human research, melatonin may benefit children with insomnia. Melatonin has been studied for sleep-wake disorders in children and adolescents. More well-designed studies that focus on safety are needed in this population.

B

Insomnia (elderly)

The production and elimination of melatonin from the body may be lower in older people with insomnia. Several human studies report that supplementing with melatonin may improve insomnia in the elderly. More research is needed before further conclusions can be made.

B

Jet lag

Several human trials suggest that melatonin taken by mouth, started on the day of travel (close to the target bedtime at the destination) and continued for several days, reduces the number of days needed to begin a normal sleep pattern, shortens the time it takes to fall asleep, improves alertness, and reduces daytime fatigue. More trials are needed to confirm these findings, determine the most effective dosing, and study the use of melatonin together with prescription sleep aids.

Studies have looked at the use of melatonin in children with mental and nervous system disorders, including mental retardation, autism, vision loss, or epilepsy (seizure disorder). More research is needed before further conclusions can be made.

B

Sleep enhancement in healthy people

People who have insomnia appear to have lower melatonin levels, and supplementing with melatonin may offer some benefit. Most human studies have been small and brief in duration. However, evidence does suggest that melatonin decreases the time it takes to fall asleep, as well as increases sleepiness and sleep duration. Melatonin may also help promote daytime sleep. More research is needed before firm conclusions can be made.

C

Age-related macular degeneration (vision loss with age)

Melatonin may have antioxidant effects, which may contribute to its eye health benefits. Research suggests that melatonin may play a role in protecting the retina to delay macular degeneration. Well-designed clinical trials are needed before a conclusion can be made.

C

Aging (body temperature regulation)

Melatonin may help regulate age-dependent changes in body temperature rhythm. More well-designed trials are needed before a conclusion can be made.

C

Alzheimer's disease/ cognitive decline

Limited research has looked at the effects of melatonin on cognitive disorders. Some studies suggest a possible benefit. In elderly people with mild cognitive impairment, a combination treatment containing melatonin improved cognitive function scores and sense of smell, as well as speech fluency. More well-designed trials are needed before a conclusion can be made.

C

Anti-inflammatory

According to limited human research, melatonin may be an effective anti-inflammatory; however, results are conflicting. Well-designed clinical trials are needed before a conclusion can be made.

C

Benzodiazepine withdrawal

A small amount of research has looked at the use of melatonin to assist with withdrawal from benzodiazepines (antianxiety drugs) such as diazepam (Valium®) or lorazepam (Ativan®). Melatonin has been studied for this purpose in people with schizophrenia. Although early results are promising, further research is needed before a firm conclusion can be reached.

C

Cancer treatment

Early human studies have looked at melatonin use in people with different types of late-stage cancer, including cancer of the brain, breast, colon, rectum, stomach, liver, lung, pancreas, testicles, immune system, skin, kidney, and soft tissues. Melatonin has been used together with many other agents and therapies. Some promising results have been found in non-small cell lung cancer and breast cancer. However, no clear conclusion can currently be made in this area. There is not enough evidence to support the use of melatonin for any type of cancer, for affecting other cancer therapies, or for reducing chemotherapy side effects.

C

Chronic fatigue syndrome

Limited research has been conducted on the effects of melatonin in people with chronic fatigue syndrome. Early results suggest a lack of effect. Further research is needed in this area before a clear conclusion can be reached.

C

Chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic lung disease that makes it difficult to breathe. Early research showed that melatonin reduced oxidative stress and shortness of breath. Changes in lung function were lacking. Further research is needed.

C

Circadian rhythm sleep disorders (people with and without vision problems)

In people with vision problems, light and dark signals are not received by the eye to trigger melatonin release and sleep. Some studies found inconclusive results for melatonin use in visually impaired children with sleep disorders. Others reported improvement in the time it takes to fall asleep and sleep duration in visually impaired people. Currently, research suggests that melatonin given in the evening may correct circadian rhythm (the internal body clock). Further research is needed before a conclusion can be made.

C

Delirium

Melatonin has been studied for delirium (confusion and changes in brain function) in people with a hip fracture and was found to reduce delirium in elderly people. More research is needed in order for conclusions to be drawn.

C

Depression

Melatonin has been suggested as a possible treatment for depression. However, human research remains inconclusive. More evidence is needed before a conclusion can be made.

C

Diabetes (additional therapy)

Melatonin used with zinc may improve blood sugar control after meals in people with type 2 diabetes. However, results are inconsistent. More evidence is needed before a conclusion can be made.

C

Exercise performance

Taking melatonin during the day may not affect jumping ability and strength. More research is needed before a conclusion can be made.

C

Fertility

Melatonin may not affect fertilization and pregnancy in people undergoing in vitro fertilization (IVF). A combination treatment containing melatonin improved both egg quality and fertilization rates in women who failed to conceive in previous IVF cycles. Further well-designed research is needed.

C

Fibromyalgia

Early studies suggest that melatonin may improve symptoms of fibromyalgia (chronic body-wide pain). Further research is needed.

C

Glaucoma

High doses of melatonin may increase eye pressure and the risk of glaucoma, age-related eye disease, nearsightedness, or retinal damage. However, early evidence suggests that melatonin may decrease eye pressure and may treat glaucoma. Further research is needed. People with glaucoma who are taking melatonin should be monitored by a healthcare professional.

C

Headache

Studies have looked at the use of melatonin for migraine, cluster, tension-type headaches, and other headache syndromes (in people who suffer from regular headaches). Melatonin has also been studied for nighttime headaches and for primary headaches in children. Limited research suggests possible benefits, but high-quality studies are needed before a firm conclusion can be made.

C

Heart disease

A combination treatment for heart disease that included melatonin was found to improve chest pain and have antioxidant, blood flow-improving, and blood pressure-lowering effects. Further high-quality research is needed.

C

High blood pressure

Studies report that melatonin may lead to small reductions in blood pressure. Melatonin may also improve cholesterol and reduce oxidative stress in people with metabolic syndrome. A combination treatment for heart disease that included melatonin was found to have blood pressure-lowering effects. Melatonin has been studied with other agents for high blood pressure in elderly people. Further research is needed.

C

High cholesterol

Early research found that melatonin used with zinc and the diabetes drug metformin may improve diabetes-related complications. Melatonin may improve blood pressure and cholesterol and reduce oxidative stress in people with metabolic syndrome. Melatonin has been studied with other agents for high blood pressure in elderly people. However, there is evidence that melatonin both increases and decreases cholesterol levels. More research is needed to clarify these mixed results.

C

HIV/AIDS

There is a lack of evidence to support or recommend against the use of melatonin for AIDS. Melatonin should not be used in place of more proven therapies. People who have HIV/AIDS should be treated under the supervision of a medical doctor.

C

Liver inflammation

Early research found that melatonin may improve liver function in people with nonalcoholic steatohepatitis (liver inflammation caused by fat buildup in the liver). Further research is needed.

C

Memory

Early research suggests that melatonin may improve memory in certain stressful situations. Further research is required before a conclusion can be made.

C

Menopause

Evidence is mixed with respect to the use of melatonin for menopause symptoms. Further research is needed before a conclusion can be made.

C

Pain

In infants requiring intubation (a tube in the mouth or nose to improve breathing), melatonin may reduce pain. Further research is needed to determine the effects of melatonin in other populations with various types of pain.

C

Parkinson's disease

There is limited research on the use of melatonin as a treatment for Parkinson's disease. Melatonin has been described as being well tolerated, but side effects may include skin flushing, diarrhea, stomach cramps, daytime sleepiness, vision changes, and headaches. Early research suggests that melatonin may improve sleep in people with Parkinson's disease. More research is needed before a firm conclusion can be made in this area.

C

Periodic limb movement disorder

There is limited study for the use of melatonin as a treatment for periodic limb movement disorder (repetitive limb movements during sleep). Although early research suggests possible benefits, further studies are needed before conclusions can be made in this area.

C

REM sleep behavior disorder

Melatonin has been suggested as a treatment for rapid eye movement (REM) sleep behavior disorder (acting out dreams during sleep), in which a person acts out vivid dreams through behaviors such as kicking, punching, and yelling. Early research describes benefits in people with this condition. However, better research is needed before a clear conclusion can be drawn.

C

Restless leg syndrome

Early research suggests that melatonin may affect motor symptoms associated with restless leg syndrome. However, evidence remains inconclusive. Further research is required in this field.

C

Rett's syndrome

Rett's syndrome is a genetic disorder that affects female children, causing slow head growth and development problems. There is limited research on the use of melatonin for improving sleep problems associated with Rett's syndrome. Further research is needed before conclusions can be made in this area.

C

Ringing in the ears

Melatonin has been suggested as a treatment for ringing the ears; this use has been supported by some early research. However, further research is needed before a conclusion can be made.

C

Sarcoidosis

Early research suggests that melatonin may be safe and effective for chronic sarcoidosis (chronic widespread inflammation) when other treatments fail or cause side effects. More research is needed before a conclusion can be made.

C

Schizophrenia

Early research suggests that melatonin may improve sleep, daytime function, and mood in people who have schizophrenia. Further research is needed.

C

Seasonal affective disorder (SAD)

Melatonin has been studied for symptoms of SAD. However, more high-quality research is needed before a clear conclusion can be reached.

C

Seizure disorder

There is controversy on the role of melatonin in seizure disorder. Melatonin has been studied in children with intractable seizures (seizures that do not respond to treatment), nervous system damage, febrile seizures (seizures triggered by a fever), and epilepsy. It has been suggested that melatonin may protect against oxidative stress and damage, as well as improve sleep quality and seizure control. However, there are reports that melatonin may actually increase the risk of seizures. Better evidence is needed in this area before a conclusion on the safety or effectiveness of melatonin can be made.

C

Skin sun damage

Several human studies have looked at the use of melatonin in protecting skin from sun damage. Although early results report reduced skin redness, further research is needed before a clear conclusion can be made.

C

Sleep disturbance

Melatonin may improve sleep disturbances in many people, including those in intensive care or those with Alzheimer's disease, mental disorders, and end-stage kidney disease. Several studies report improved sleep patterns in young people with brain damage caused by tumors or surgery. Melatonin has been proposed as a therapy for disease caused by exposure to light during the nighttime, as well as for sleep disorder in elderly people with dementia. Early research suggests that melatonin may also be useful for people with asthma and depression; however, results are limited and/or inconclusive for those with Parkinson's disease, bipolar disorder, and schizophrenia, or those undergoing in vitro fertilization (IVF). Depending on the condition, melatonin may or may not be an effective sleep aid.

C

Smoking

Limited research has looked at the use of melatonin for symptoms of smoking withdrawal, including anxiety, restlessness, irritability, and cigarette craving. Although early results are promising, further research is necessary before a firm conclusion can be reached.

C

Stomach disorders (and intestine disorders)

Early research suggests that melatonin may benefit people with indigestion and acid reflux disease. When used with traditional therapy, melatonin may reduce inflammation in people with Crohn's disease and ulcerative colitis (inflammatory bowel diseases that affect the intestines). Melatonin has also been studied for irritable bowel syndrome. More research is needed in this field.

C

Stroke

Melatonin has been proposed as a treatment for nervous system damage after a stroke, based on its antioxidant effects. Melatonin levels may also be changed following a stroke, and it has been suggested that supplementing with melatonin may have benefits. However, human evidence is lacking at this time.

C

Surgery

Limited studies have compared melatonin to standard drugs for anxiety before surgery. Melatonin has also been suggested as a treatment for delirium (confusion) following surgery. However, evidence is mixed, and further research is needed before a clear conclusion can be drawn.

C

Tardive dyskinesia

Tardive dyskinesia (involuntary muscle movements) is a serious potential side effect of medications for mental disorders. Limited studies report mixed findings on melatonin use in people with TD. Further research is needed before a clear conclusion can be drawn.

C

Thrombocytopenia (low platelets)

Thrombocytopenia is a condition in which platelets (parts of the blood that help promote clotting) are low. Higher platelet counts have been seen after melatonin use in people with low platelets due to cancer therapies. Stimulation of platelet production has been suggested but not proven. More research is needed in this area before a clear conclusion can be drawn.

C

Ulcers

Early evidence suggests that melatonin may aid in the healing of ulcers. Further well-designed research is needed.

C

Urination (waking up at night to urinate)

Melatonin may benefit elderly people who wake up during the night to urinate, but not teens and adolescents. Early research has produced conflicting results. More research is needed before a conclusion can be made.

D

Work shift sleep disorder

Several studies have looked at melatonin use in people who work irregular shifts, such as emergency room personnel. Results are mixed. Further research is necessary before a clear conclusion can be drawn.

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Interactions

Interactions with Drugs

Note: This section discusses both melatonin in the body and melatonin from other sources, and the effects of other agents on melatonin and when taken with melatonin. Many drugs may lower natural melatonin levels in the body. These include nonsteroidal anti-inflammatory drugs (NSAIDs, including ibuprofen [Motrin®, Advil®] or naproxen [Naprosyn®, Aleve®]), beta-blocker blood pressure medications (including propranolol [Inderal®], atenolol [Tenormin®], and metoprolol [Lopressor®, Toprol®]), and agents that lower levels of vitamin B6 in the body (including birth control, hormone replacement therapy, loop diuretics, hydralazine, and theophylline). Other agents that may affect melatonin levels include caffeine, diazepam, estradiol, somatostatin, temazepam, verapamil, and vitamin B12.

Melatonin may affect the risk of clotting. Caution is advised in people with bleeding or clotting disorders and those taking drugs that may affect bleeding or clotting. Dosing adjustments may be necessary.

Melatonin may affect blood sugar levels. Caution is advised when using medications that may also affect blood sugar. People taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Melatonin may affect blood pressure. Caution is advised in people taking drugs that affect blood pressure.

Melatonin may interfere with the way the body processes certain drugs using the liver's cytochrome P450 enzyme system. As a result, the levels of these drugs may be altered in the blood and may cause altered effects or potentially serious adverse reactions. People using any medications should check the package insert and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Melatonin may increase the amount of drowsiness caused by some drugs. Examples include benzodiazepines such as lorazepam (Ativan®) or diazepam (Valium®), barbiturates such as phenobarbital, narcotics such as codeine, some antidepressants, and alcohol. Caution is advised while driving or operating machinery.

Interactions with Herbs and Dietary Supplements

Note: This section discusses both melatonin in the body and melatonin from other sources, and the effects of other agents on melatonin and when taken with melatonin. Many drugs may lower natural melatonin levels in the body. These include nonsteroidal anti-inflammatory drugs (NSAIDs, including ibuprofen [Motrin®, Advil®] or naproxen [Naprosyn®, Aleve®]), beta-blocker blood pressure medications (including propranolol [Inderal®], atenolol [Tenormin®], and metoprolol [Lopressor®, Toprol®]), and agents that lower levels of vitamin B6 in the body (including birth control, hormone replacement therapy, loop diuretics, hydralazine, and theophylline). Other agents that may affect melatonin levels include caffeine, diazepam, estradiol, somatostatin, temazepam, verapamil, and vitamin B12.

Melatonin may affect the risk of clotting. Caution is advised in people with bleeding or clotting disorders and those taking herbs and supplements that may affect bleeding or clotting. Dosing adjustments may be necessary.

Melatonin may affect blood sugar levels. Caution is advised when using herbs or supplements that may also affect blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Melatonin may affect blood pressure. Caution is advised in people taking herbs or supplements that affect blood pressure.

Melatonin may interfere with the way the body processes certain herbs or supplements using the liver's cytochrome P450 enzyme system. As a result, the levels of other herbs or supplements may alter in the blood. It may also alter the effects that other herbs or supplements possibly have on the cytochrome P450 system.

Melatonin may increase the amount of drowsiness caused by some herbs or supplements.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid with known allergy or sensitivity to melatonin or related products. Melatonin has been linked to allergic skin reactions and autoimmune hepatitis (liver inflammation caused by immune cells attacking the liver).

Side Effects and Warnings

Melatonin is likely safe when taken by mouth in commonly studied doses for up to three months, typically 1-20 milligrams. In children, melatonin is likely safe for long-term use in recommended doses.

Melatonin may affect blood pressure. Caution is advised in people taking drugs, herbs, or supplements that affect blood pressure.

Melatonin may affect blood sugar levels. Caution is advised in people with diabetes or low blood sugar and those taking drugs, herbs, or supplements that affect blood sugar. Blood sugar levels may need to be monitored by a qualified healthcare professional, including a pharmacist, and medication adjustments may be necessary.

Melatonin may affect the risk of clotting. Caution is advised in people with bleeding or clotting disorders and those taking drugs that may affect bleeding. Dosing adjustments may be necessary.

Drowsiness or sedation may occur. Use caution in people who are driving or operating heavy machinery (including aircraft) and those taking depressants, stimulants, or sedatives.

Melatonin may interfere with the way the body processes certain drugs using the liver's cytochrome P450 enzyme system.

Use cautiously in people who have or are at risk of changes in hormone levels, eye disorders, frequently feeling cold, genital or urinary disorders (including children with a history of bedwetting), heart disease, hyperactivity, immune disorders, inflammatory disorders, mental disorders, muscle control problems, nervous system disorders, seizures, skin disorders, and stomach and intestinal problems.

Use cautiously in people taking agents that affect the immune system, anti-inflammatory agents, or hormonal agents.

Use cautiously in breastfeeding women, due to a lack of safety information.

Avoid in women who are pregnant or trying to get pregnant. Melatonin may decrease sex drive, increase the risk of developmental disorders, and reduce ovarian function.

Avoid in people with known allergy or sensitivity to melatonin or related products.

Pregnancy and Breastfeeding

Overall, there is a lack of high quality scientific evidence on the use of melatonin during pregnancy or breastfeeding.

Use cautiously in breastfeeding women, due to a lack of safety information.

Avoid in women who are pregnant or trying to get pregnant. Melatonin may decrease sex drive, increase the risk of developmental disorders, and reduce ovarian function.

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